Laboratory Studies of Galvanic Corrosion I. Two-Metal Couples

Abstract

Abstract Galvanic interaction of stainless steel 304L, Ni 270, Cu, Ti-6AI-4V, Sn, 4130 steel, Cd, and Zn has been studied in 3.5% NaCl using galvanic current and weight loss measurements in 24-hour tests. Galvanic couples of 4130 steel and one of the Al alloys 1100, 2024, 2213, 6061, and 7075 have also been evaluated in tap water and distilled water. Galvanic current data can be used to assess both the effect of different dissimilar cathode materials as well as the relative susceptibility to galvanic corrosion of anode materials. For 3.5% NaCl, it has been found that the effect of the cathode material decreases in the order Cu > Ni > stainless steel >Ti-6Al-4V, while the relative susceptibility of anode materials decreases in the order Sn > Zn > 4130 steel > Cd. An analysis of data in various electrolytes shows that coupling of 4130 steel to Al alloys leads to cathodic protection of the steel in 3.5% NaCl, but to accelerated corrosion in tap water and distilled water.